Since the home laundering operation is performed frequently in millions of homes throughout the United States and the world, much work has been done in an effort to make the operation more convenient and efficient. The laundry procedure generally requires the measuring and adding to the washing machine of a detergent composition as well as other laundry additives, such as bleaches, static control agents and fabric softeners. Thus, it would be desirable to use an article containing premeasured amounts of these compositions, which could be easily added to the washing machine without additional measuring.
Packages or articles containing premeasured amounts of laundry detergent compositions provide the user with a convenient way to add the detergent to an automatic washing machine, while simultaneously eliminating the necessity of measuring operations and their accompanying spillage and waste. In addition, desirable laundry additives, such as bleaches, static control agents and fabric softeners, may also be included in the package, thereby allowing the user to obtain multiple cleaning and fabric care benefits by simply dropping the premeasured portion into the washing machine at the beginning of the laundry operation. Prepackaged, premeasured articles must exhibit certain properties in order to be useful in the laundering operation. For example, as a result of the inherent nature of surface-active agents the articles must be formulated so as to be easy to handle and store, and should not be overly sticky when handled by the user, or when manufactured and packaged. Further, the articles must have a structure such that a sufficiently large amount of the detergent composition will be released into the washing solution during the relatively short washing cycle, in order to assure proper cleaning.
Premeasured laundry detergent compositions have been included in tablets and in water-soluble packets, such as those described in U.S. Pat. Nos. 3,503,889, Davis et al, issued Mar. 31, 1970; 3,198,740, Dunlop et al, issued Aug. 3, 1965; 3,413,229, Bianco et al, issued Aug. 26, 1968; and 3,186,869, Friedman, issued June 1, 1965.
Water-insoluble substrates have been used to introduce various active ingredients into certain laundering and washing operations. For example, U.S. Pat. No. 3,422,692, Gaiser, issued May 6, 1969, teaches a method for softening and controlling static on fabrics in a laundry washer or dryer, utilizing a fabric conditioning composition combined with a single layer substrate. See also U.S. Pat. No. 3,632,396, Perez Zamora, issued Jan. 4, 1972; and U.S. Pat. No. 3,686,025, Morton, issued Aug. 22, 1972. Such single layer substrates would generally not be useful for introducing laundry detergent compositions into a washing solution since it would be difficult to load the relatively large amounts of the compositions, which are required where conventional detergent active systems are used, on the substrate sheet. Further, single sheet articles would generally be quite sticky or uncomfortable to the touch and, therefore, would be difficult to handle and store, and could cause manufacturing and packaging problems.
Articles used for scrubbing, which have multiple substrate layers containing a cleaning composition, have been disclosed. Such a structure could solve the handling problem, described above, since the active system is completely surrounded by substrate layers. U.S. Pat. No. 2,389,736, Muise, issued Nov. 27, 1945 and Japanese Utility Model 02940/75, Kokoku Chemical Industry Company, Ltd., published Jan. 13, 1975, disclose this type of soap-containing article for use in the scrubbing of the hands and body. U.S. Pat. No. 2,655,528, Sternfield et al, issued Jan. 12, 1954, and U.S. Pat. No. 3,121,249, Affleck et al, issued Feb. 18, 1964, disclose this type of structure for disposable articles used in the washing and scrubbing of hard surfaces, such as dishes and counter tops. These articles rely on physical rubbing and scrubbing during use to assure the release of the proper amount of cleaning composition for the cleaning operation. Further, since many of these articles may be reused before they are discarded, it is important that they be formulated such that only a fraction of the cleaning composition contained in the article be released during any single use of the article.
It has now been found that by selecting water-insoluble substrate materials having specifically defined air permeability and surface area characteristics, a detergent article containing a laundry detergent composition between layers of this material, which yields complete or substantially complete release of the detergent composition into the washing solution during a conventional automatic laundering operation, and which is easy to handle and store, may be formulated. In addition, other desirable laundry benefits, such as bleaching, fabric softening and static control, may also be delivered to the laundered fabrics using the substrate articles of the present invention. An example of the delivery of such benefits is disclosed in concurrently filed U.S. Pat. No. 4,095,946, issued June 20, 1978, Jones and Kingry, Article for Cleaning and Conditioning Fabrics, incorporated herein by reference.
It is therefore an object of the present invention to provide a substrate article which effectively and conveniently cleans fabrics during a conventional automatic fabric laundering operation.
It is a further object of this invention to provide a substrate article which is not overly sticky when handled, and therefore is easy to manufacture, use and store.
It is a still further object of this invention to provide a substrate article which cleans fabrics during a conventional automatic laundry operation and which may be used to deliver additional benefits to the fabrics in both the automatic washer and subsequently in the automatic dryer.
It is also an object of this invention to provide a method for obtaining cleaning benefits for fabrics, utilizing a substrate detergent article.